Nowadays, gaskets are used in many technical fields. One of those fields comprises internal combustion engines where the gaskets are used as cylinder head gaskets. In this case, the gaskets are arranged between the cylinder head and the cylinder block of the internal combustion engine. Combustion chambers, coolant and lubricant passageways and passageways for attaching means which keep together the cylinder head, the gasket and the cylinder block, are assigned to the through-holes. It is in particular the metal ring which is the reason for the sealing capacity of the gasket. When the attaching means are mounted or when the internal combustion engine is operated, the metal ring acts against an external force acting on the gasket. One further technical field where gaskets of the type referred to here are used, comprise for example exhaust gas modules in automotive vehicles where the gaskets are mainly used as exhaust gaskets.
The metal ring can be attached to the metal layer using several methods. One of these methods comprises welding the metal ring to the metal layer, as it is described in the German published patent application DE 195 48 236 A1. According to this method, the metal ring is brought into contact with the metal layer and pressed to the latter by means of welding electrodes. A welding current flows through the welding electrodes to the metal ring and the metal layer. The welding current heats up certain portions of the metal ring and the metal layer. Within these portions, the metal ring and the metal layer material joins whereby a welding joint between the metal ring and the metal layer is formed.
Practice has shown that in gaskets which have been manufactured according to the described method, the metal ring and the metal layer can become detached which means that the welding joint is not stable. This effect is disadvantageous for the sealing capacity of the gasket.
Therefore, it is an object of the invention to provide a gasket the welding joints of which are stable. Moreover, it is an object of the invention to develop a method for manufacturing such gaskets.